Alzheimer's dementia

Synonyms in the broader sense

Alzheimer's disease, dementia, Alzheimer's

definition

A Alzheimer's dementia is a degenerative brain disease that causes dementia leads. Reasons for the decline of brain function (degeneration) are the sinking of cores of the central nervous system, the messenger substances (Transmitter) produce, and the tissue shrinkage (atrophy) of the Cerebral cortex. At the same time there is an excessive deposition of certain substances in brain and cerebral vessel walls.

Epidemiology

Alzheimer's disease is considered to be the most common cause of dementia in western nations and is responsible for 50-75% of all dementias. In Asian countries, however, in contrast to Europe and the USA, another form of dementia, vascular dementia, appears to be more common than dementia of the Alzheimer's type.

The frequency of the disease is age-dependent. In the age group under 60 it is around 0.04%, up to the age of 70 around 1%, between 70 and 79 years around 3% and between 80 and 90 years around 10%.There are various sources of information about people over 95: On the one hand, it is reported that the frequency decreases again at this age, on the other hand, it is claimed that 40-50% are sick. In general, however, it can be said that around 5% of all over 65-year-olds suffer from dementia, 50-75% of them from Alzheimer's disease.

The main age of the disease is between 70 and 80 years of age. Women get sick comparatively more often, but probably only because their share in this age group is much larger than that of men. The rare, familial form has a younger age of onset.

In a patient with Trisomy 21 ("Down syndrome") the risk of Alzheimer's dementia is increased many times over. See also Alzheimer's causes

history

Alzheimer's disease was first published in 1901 by the German doctor Alois Alzheimer (1864-1915) described as a "strange clinical picture". The patient he described was Auguste Deter, then 51. She had a noticeable memory impairment at an early age, associated with disorientation and hallucinations, which led to her death at the age of 55 in 1906. After her death, Alzheimer's examined her brain and discovered some abnormalities: The cerebral cortex was thinner than normal and he found focal deposits that "Alzheimer's plaques and -Fibrils“.

In the following five years, further cases of patients with a similar disease were already classified as "Alzheimer's disease“Described in the medical literature. The official name goes to the psychiatrist Emil Kraepelin back, with whom Alzheimer worked for a number of years. In 1910 he named the disease in his "textbook on psychiatry" after Alois Alzheimer.

genetics

Genetic factors play a role as further causes of Alzheimer's disease. 7% of all patients with Alzheimer's disease have a familial accumulation of dementia. These patients are summarized in the familial Alzheimer's dementia (FAD) group. In some of these cases, Alzheimer's disease is caused by a dominantly hereditary genetic defect. The defective genes are located on chromosomes 1, 14 and 21.

The mutations on chromosome 1 and 14 affect the genes of the presenilin proteins. If presenilin-1 on chromosome 14 is affected, the onset of the disease occurs before the age of 60, in the extreme form before the age of 30. A mutation in the presenilin-1 gene is the most common cause of familial Alzheimer's dementia with early onset.

If presenilin-2 on chromosome 1 is affected, the age of onset is between 45 and 73 years of age. Both proteins are related to the breakdown of protein-containing deposits in tissue (Amyloid). Mutations in the amyloid precursor protein (amyloid precursor protein (APP)) on chromosome 21 lead to the onset of the disease before the age of 65.

Within the group of Alzheimer's dementia caused by genetic defects, a mutation can be found on chromosome 14 in 80% of patients, on chromosome 1 in 15% and on chromosome 21 in 5%.

In trisomy 21, dementia is the rule in those over 30 years of age, and changes in the brain that are very similar to those in Alzheimer's disease can be discovered.

A defect in the gene for apolipoprotein E on chromosome 19 can also be the cause of Alzheimer's dementia, since apolipoprotein E reacts with amyloid and thus accelerates the accumulation (aggregation) of amyloid into plaques. It is also related to certain neurological symptoms that can occur in Alzheimer's patients.

For general information see also: The dementia